Dynamic illumination using a coherent light source

ABSTRACT

An illumination source, comprising: (a) at least one coherent light emitting device (CLED) configured for emitting coherent light having an optical path; (b) at least one optical element in said optical path for converting at least a portion of said coherent light to incoherent light, said optical element being configured to emit said incoherent light in a direction; and (c) a light control mechanism (LCM) for altering said direction of said incoherent light.

REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/852,222, filed on May 23, 2019, and U.S. Provisional Application No.62/852,218, filed on May 23, 2019, both of which are incorporated hereinby reference in their entirety including their appendices

FIELD OF DISCLOSURE

This disclosure relates generally to using coherent light devices, suchas lasers, in illumination sources, and more specifically to dynamicallycontrolling coherent light sources to adjust the direction, shape,and/or quality of the emitted light of illumination sources.

BACKGROUND

Light emitting diodes (LEDs) have become a popular choice for lightingapplications. LED lamps are significantly brighter, more efficient, andhave a lifespan much longer than incandescent lamps. Although LEDs havesignificant benefits over traditional incandescent light sources,Applicant recognizes that a light source having a smaller beam ofspatially coherent light, such as laser, may provide improved efficiencyover LEDs in some illumination applications, such as spot lighting andlinear accents. In addition, the smaller source size of the laser canlead to improved dynamic optical control and enable applications such asentertainment lighting and way finding. Moreover, as the cost of lasers,particularly for vertical cavity surface emitting lasers (VCSELs),continues to drop, their appeal in lighting applications increases.

While the smaller beam and source size of lasers may be beneficial,coherent light emitted from lasers also presents challenges.Specifically, coherent light is not only monochromatic, but alsopotentially hazardous to eyes/retina and other tissues. For this andother reasons, the adoption of lasers in commercial and residentiallighting applications is still in its infancy.

Applicant recognizes the need for a dynamic illumination using coherentlight while avoiding the hazards of coherent light. The presentinvention fulfills this need among others.

SUMMARY OF INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an extensive overview of the invention. It is notintended to identify key/critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome concepts of the invention in a simplified form as a prelude to themore detailed description that is presented later.

Applicant recognizes that while coherent light presents challenges inconnection with its monochromicity and its potential hazard toeyes/retina, it also presents an enhanced ability to control thedirection, shape and quality of the emitted light compared to incoherentlight sources. For example, in one embodiment, the direction of theincoherent emitted light is controlled by controlling the direction ofthe coherent light. In another embodiment, the outputs of differentwavelength coherent light sources are combined and balanced to achievedesired spectrums for white light, circadian-friendly lighting, and/orantibacterial lighting, just to name a few.

In one embodiment, an illumination source comprises: (a) at least onecoherent light emitting device (CLED) configured for emitting coherentlight having an optical path; (b) at least one optical element in theoptical path for converting at least a portion of the coherent light toincoherent light, the optical element being configured to emit theincoherent light in a direction; and (c) a light control mechanism (LCM)for altering the direction of the incoherent light.

In another embodiment, an illumination source comprises: (a) an array ofcoherent light emitting devices (CLEDs), each CLED configured foremitting coherent light having an optical path, at least two or more ofCLEDs configured for emitting coherent light having differentwavelengths, wherein the array of CLEDs comprises separatelycontrollable drivers controlled by a control signal such that the outputof at least a portion of the array of CLEDs is variable based on thecontrol signal; and (b) at least one optical element in the optical pathfor converting at least a portion of the coherent light to incoherentlight.

BRIEF DESCRIPTION OF FIGURES

FIG. 1A shows one embodiment of the illumination source of the presentinvention having an array of CLEDs of the same wavelength with movablelenses in the optical path of the coherent light to alter the directionof emitted incoherent light.

FIG. 1B shows the embodiment of FIG. 1A with the lenses shifted tochange the direction of the emitted incoherent light.

FIG. 2 shows an embodiment of the illumination source, similar to thatof FIG. 1A, but with CLEDs of different wavelengths.

FIGS. 3A-3C show different embodiments of the light control mechanism(LCM) of the present invention.

FIGS. 4A-4F show different embodiments of the actuators used in the LCMof the present invention.

FIG. 5A shows one embodiment of the illumination source of the presentinvention.

FIG. 5B shows the luminaire FIG. 5A with the coherent beam altered tochange the direction of the emitted incoherent light.

FIG. 6 shows one embodiment of a MEMS for altering the position of thelenses.

FIG. 7 shows one embodiment of an array of phosphors.

FIG. 8 shows the combination of the MEMS of FIG. 6 and the array ofphosphors of FIG. 7 .

FIG. 9 shows another embodiment of the LCM in which a metasurface isused.

FIG. 10 shows an embodiment of a luminaire comprising a light sourceusing a metasurface to alter the path of the coherent beam to change theemitted incoherent light.

FIG. 11A shows an embodiment of an LCM using a metasurface to change thedirection of multiple coherent beams transmitted from an array of CLEDs.

FIG. 11 B is similar to the embodiment of FIG. 11A, except that theCLEDs have different wavelengths.

FIG. 12 shows an embodiment of the LCM in which metasurfaces steercoherent beams of different wavelengths to a particular point on adiffuser, and the LCM comprises lenses to alter the direction of theemitted incoherent light.

FIGS. 13A-13E show various embodiments of LIFI in luminaires using thedifferent embodiments of the illumination sources described herein.

FIG. 14 shows one embodiment of a flashlight having a TO can with thephosphor window.

DETAILED DESCRIPTION

In the following paragraphs, the present invention will be described indetail by way of example with reference to the attached drawings.Throughout this description, the preferred embodiment and examples shownshould be considered as exemplars, rather than as limitations on thepresent invention. As used herein, the “present invention” refers to anyone of the embodiments of the invention described herein, and anyequivalents. Furthermore, reference to various feature(s) of the“present invention” throughout this document does not mean that allclaimed embodiments or methods must include the referenced feature(s).

Referring to FIGS. 1A and 1B, one embodiment of an illumination source100 of the present invention is shown. In this embodiment, theillumination source 100 comprises at least one coherent light emittingdevice (CLED) 101 configured for emitting coherent light 102 having anoptical path. At least one optical element 103 is disposed in theoptical path for converting at least a portion of the coherent light toincoherent light 110, the optical element being configured to emit theincoherent light in a direction. The illumination source also comprisesa light control mechanism (LCM) 104 for altering the direction of theincoherent light. As used herein, the term “coherent light” refers tolight that has either temporal or spatial coherence, and the term“incoherent light” refers to light that has neither temporal nor spatialcoherence.

Referring to FIG. 2 , another embodiment of an illumination source 200of the present invention is shown. In this embodiment, the illuminationsource 200 comprises an array of CLEDs 201, each CLED configured foremitting coherent light having an optical path, at least two or more ofCLEDs 201 a, 201 b, 201 c, configured for emitting coherent light havingdifferent wavelengths. The array of CLEDs also comprises separatelycontrollable drivers (not shown) controlled by a control signal suchthat the coherent light output 202 a, 202 b, 202 c of at least a portionof the array of CLEDs 201 a, 201 b, 201 c is variable based on thecontrol signal. At least one optical element 203 is disposed on theoptical path of the coherent light output for converting at least aportion of the coherent light to incoherent light 210.

These elements are described below in greater detail and in the contextof selected alternative embodiments.

LCM

The LCM functions to change either the direction and/or the shape of theincoherent light being emitted from the illumination source. The LCM hasvarious embodiments that function to change the direction and/or shapeof the incoherent light in different ways. For example, in oneembodiment, the LCM changes the direction of the incoherent light bybending the coherent light. Alternatively, rather than bending thecoherent light, the LCM moves the CLED to change the optical path of thecoherent light. In still another embodiment, the LCM alters thedirection of the incoherent light by bending the incoherent light as itleaves the optical element. These different approaches are described indetail below in connection with various configurations of the LCM. Stillother embodiments of the LCM will be obvious to those of skill in theart in light of this disclosure.

Referring to FIGS. 1A and 1B, one embodiment of the LCM 104 is shown inwhich the optical path 102 of the coherent light from the CLED 101 isbent. In this embodiment, the LCM comprises at least one second opticalelement 105 in the optical path before the optical element 103, and anactuator 106 operatively connected to the second optical element tochange at least one characteristic of the second optical element inresponse to a control signal, wherein changing the characteristic causesthe optical path to change such that the incoherent light being emittedfrom the optical element changes its direction.

In this particular embodiment, the second optical element 105 is atleast one lens, and the actuator 105 changes a position characteristicof the lens relative the CLED. The lens may be a discrete lens opticallycoupled with a discrete CLED, or it may be an array of lenses opticallycoupled to an array of CLEDs. Such lenses and their fabricationtechniques are well-known in the art. For example, in one embodiment,cyclic olefin copolymer (COC) may be used if the lenses are molded, andbenzocyclobutene (BCB) may be used if the lenses are prepared usinglithographic patterning.

In one embodiment, changing the position characteristic comprises movingthe lens laterally with respect to the axis of the optical path as shownin FIG. 1B. As the lenses are moved laterally, the optical path 102 a isbent causing its angle of incidence upon the optical element 103 tochange. This change thereby affects the direction of the incoherentlight emitted from the optical element 103.

Alternatively, rather than actuating the lenses laterally with respectto the optical axis, the lenses may be actuated axially with respect tothe optical axis, or they may be tilted on their z axis (optical axis).Still other approaches for actuating the lenses will be known to thoseof skill in the art in light of this disclosure.

In one embodiment, the actuator 106 functions to move one or more lensesto affect the optical path of either the coherent light or theincoherent light, or both. The actuator may have various embodiments,including those based on micro-electromechanical system (MEMS)positioning systems, piezoelectric actuators, and even manual actuators.For example, referring to FIG. 6 , one embodiment of the actuator 606 isshown comprising a MEMS positioning system. This particular MEMs is acomb drive (electrostatic) MEMS, which is well suited for x/ytranslation. In another embodiment, in which the movement of the lens isnot in the xy-direction, but instead, for example, involvestipping/tilting the lens along the optical axis, then another MEMS, suchas bimporph (electrothermal) actuator, may be preferable.

Referring back to FIG. 6 , the MEMS embodiment of FIG. 6 is a 4×3 arrayof MEM elements. In this embodiment, each MEM element 650 comprises oneset of x-direction electromechanical actuators 651 and one set ofy-direction electromechanical actuators 652. Although this LCMembodiment is configured as a 4×3 array, other embodiments are possibleincluding a single element MEM or arrays of any number. It should benoted that the driving circuitry for driving the MEMS in the XYdirection is not shown, but is well known to those of skill in the art.

In one embodiment of the LCM of FIG. 8 , the MEMS facilitates theindependent movement of each lens in an array of lenses. In other words,each lens 750 of the array of lenses 705 may correspond to a separatelycontrollable MEMS element 650, such that the movement of each lens canbe controlled discretely. Alternatively, rather than actuating lensesindividually, the entire array may be moved as a unit. For example,referring to FIGS. 3A-3C, various embodiments are shown in which theentire lens assembly is moved rather than discrete lenses within anarray. For example, referring to FIG. 3 , one embodiment of theillumination source 300 a is shown, comprising a ceramic package 331 inwhich is mounted a CLED 301 a. The ceramic package 331 is mounted on aPCB or submount or heatsink 330 as shown. This ceramic package 331comprises walls upon which MEMS 306 are mounted. Attached to the MEMS306 is a lens 305 a as shown. In this embodiment, a single lens is movedusing the MEMS.

Alternately, in FIG. 3B, an illumination system 300 b is shown which issubstantially similar to that of 300 a, but rather than a singlediscrete lens 305 a, a microlens array 305 b is shown. In this case theentire array of lenses is moved as one by the MEMS 301 b as shown.

In yet another embodiment shown in FIG. 3C, the illumination source 300c is not a ceramic package 331 as shown in FIGS. 3A and 3B, but rathercomprises discrete a discrete ceramic substrate upon which the CLED 301c is mounted. The ceramic substrate is mounted to a PCB. On either sideof the ceramic substrate are standoffs with electrical interconnects332. As with the illumination source 300 b, illumination source 300 cuses a MEMS 306 to move the entire array of lenses 305 c as one. Stillother embodiments will be obvious to those of skill in the art in lightof this disclosure.

Rather than bending the optical path of the coherent light using a lens,in another embodiment, the optical path of the coherent light is alteredusing a metasurface. Beam steering with metamaterials is known.Metasurfaces can be designed to deflect the laser beam and/or change thebeam shape. For example, a metasurface can modify the beam shape forfiber coupling—e.g., multi-lobes can be created, and the beams can becoupled into two different fibers without external optics.

Referring to FIG. 9 , one embodiment of the illumination source 900 isshown in which the second optical element of the LCM 904 is at least onecontrollable metasurface 990, and the actuator changes at least one ormore metaatom characteristics of the metasurface to thereby change thedirection of the optical path 902 of the coherent light as shown. In theembodiment shown in FIG. 9 , the optical path 902 is reflected off ofthe metasurface 990 at different angles depending upon thecharacteristics of the metasurface. Here, the coherent light 902 isgenerated from a surface emitting CLED 901 mounted, for example, on asubstrate, and is reflected off of the metasurface 990 and into theoptical element 903, which, in this case, happens to be adown-converter.

The angle at which light is reflected off the metasurface depends uponthe characteristics of the metasurface. The actuator is configured tochange these characteristics to obtain the desired angle of reflection.For example, the actuator may change the size, shape and distancebetween metaatoms of the metasurface. To this end, the actuator maystimulate the metasurface using at least one of an electric field, anelectrostatic force, optical tuning (plasmonics), and/or manipulatingoptical nonlinearity (Mie resonators). Such stimulation techniques areknown. For example, in some LIDAR applications the metasurface iscombined with liquid crystals where changing voltage across themetasurface (optical antennas) with liquid crystals changes causes thedirection of the beam to change. The same configuration may be used forvisible light steering. The phase delay is proportional to the appliedvoltage which rotates the liquid crystals and shifts the resonantwavelength. Still other means of altering the characteristics of themetasurface will be known to those of skill in the art in light of thisdisclosure.

The illumination source 900 may be configured in different ways whenpackaged in a luminaire. For example, referring to FIG. 10 , a luminaire1000 using one embodiment of the illumination source 1010 of the presentinvention is shown. In this embodiment, the luminaire 1000 comprises ahousing 1003 in which the illumination source 1010 is housed. Theillumination source 1010 comprises a CLED 1001, which, in thisembodiment, is an edge emitting device. It is configured such that thecoherent light being emitted therefrom has an optical path incident upona second optical element 1004, which, in this embodiment, is ametasurface 1011. Depending upon the characteristics of the metasurface1011, the coherent light is reflected at various angles. The reflectedlight is incident upon the optical element 1003 which, in thisembodiment, is a down-converter. As mentioned above, by varying theangle of incidence upon the optical element 1003, the incoherent light1011 emitted therefrom varies as well. In this embodiment, theincoherent light is coupled to a lens 1012 which is configured to shapethe incoherent light 1011 emitted from the luminaire 1000. It should beunderstood that this is just one embodiment of a luminaire of using theillumination source of the present invention. Still other embodimentswill be readily apparent to those of skill in the art in light of thisdisclosure.

In yet another embodiment, the LCM comprises at least one actuatoroperatively connected to the CLED to move the CLED in response to acontrol signal, wherein moving the CLED causes the optical path tochange such that the incoherent light being emitted from the opticalelement changes its direction. For example, referring to FIGS. 4A-4F,various embodiments of an LCM for changing the direction of the opticalpath of the coherent light are shown. Generally speaking, these LCMembodiments differ from the aforementioned embodiments in that, ratherthan bending or having the optical path reflected as described above,the orientation of the CLED is changed to alter the direction of theoptical path of the coherent light.

More specifically, referring to FIGS. 4A and 4B, an embodiment of alight source subassembly 400 a is shown. The subassembly 400 a comprisesa single CLED in a ceramic package 442 and the optical element 403 is adown-converter. This particular embodiment also comprises a lens 405Afor shaping the incoherent light 411. The LCM in this embodimentcomprises actuators 406, which are configured to move the entire ceramicpackage 422 to change the direction of the coherent light 402, and thusthe incoherent light 411. More specifically, referring to FIG. 4A, theoptical subassembly 400 a has a neutral state in which the coherentlight 402 is being emitted essentially perpendicular to the substrate450. In FIG. 4B, the actuators 406 are actuated such that the coherentlight 402 is emitted from the subassembly at an angle to the substrate,causing the incoherent light 411 to be emitted at an angle to thesubstrate as well.

Referring to FIGS. 4C and 4D, an embodiment of the optical subassembly400 b, similar to that of FIGS. 4A and 4B, is shown. Like subassembly400 a, subassembly 400 b comprises a ceramic package 442 mounted onactuators 406 and a down-converter optical element 403. However, unlikesubassembly 400 a, subassembly 400 b comprises an array of CLEDs and amicrolens array 405 b. Regardless of the embodiment, actuating theactuators 406 causes the incoherent light 411 to change direction fromthe neutral state shown in FIG. 4C to the actuated state shown in 4D.

Referring to FIGS. 4D and 4F, yet another embodiment of a subassembly400 c is shown. In this embodiment, a plurality of subassemblies 400 bare mounted on a substrate such as a PCB board 444. However, in thisembodiment, the actuators 406 are not connected directly to the ceramicpackage 442 as in the embodiments of FIGS. 4A and 4B, but ratherconnected to the substrate 444 upon which the subassemblies 400 b aremounted. Thus, moving the substrate moves the plurality ofsubassemblies, causing the incoherent light 411 to change direction fromthe neutral position as shown in FIG. 4 e to the actuated position asshown in 4F.

A variety of different actuators can be used in the embodimentsconsidered above. Although the embodiments disclosed above used eitherpiezoelectric actuators or MEMS, the two approaches may beinterchangeable. Additionally, other approaches exist. For example, inyet another embodiment, actuation of the lens or array of lenses isperformed manually. For example, the illumination source may have anexternal lever or screw mechanism which the user can manipulate toaffect the position of the lens, and therefore alter the direction/shapeof the incoherent light leaving the illumination source. Still otheractuation mechanisms will be obvious to those of skill in the art inlight of this disclosure.

In yet another embodiment, the LCM comprises at least one second opticalelement configured to receive at least a portion of the incoherentlight, and an actuator operatively connected to the second opticalelement to change at least one characteristic of the second opticalelement in response to a control signal, wherein changing thecharacteristic causes the incoherent light to change its direction. Inother words, rather than altering the optical path of the coherentlight, in this embodiment, the path of the coherent light is fixed, andthe optical path of the incoherent light is changed. For example,referring to FIG. 12 , in this embodiment of the illumination source1200, the LCM 1204 comprises one or more lenses 1205 in the optical pathof the incoherent light 1211. The lenses are operatively connected to aMEMS actuator 1206, such that, when moved by actuator 1206, the opticalpath of the incoherent light 1211 changes. In this respect, the LCM 1204is similar to the LCM 104 except the LCM 104 alters the optical path ofthe coherent light, while LCM 1204 alters the optical path of theincoherent light.

Another embodiment in which the LEM alters the optical path of thecoherent light is shown in FIG. 14 . Referring to FIG. 14 , a flashlight1450 is shown comprising one embodiment of illumination source of thepresent invention. Specifically, the flashlight 1450 comprises a TO can1402 with the phosphor window 1403 for converting coherent lightgenerated from a laser within the TO can to substantially white light.In this particular embodiment, the flashlight comprises also comprises adriver circuit 1451 for driving the TO can, a connection 1452 to abattery 1463 and a connection 1454 from the battery to a power button1455. In this embodiment, to shape the light, the LCM modifies theincoherent light using a reflector 1456, lens 1457 and actuator 1458.The actuator is threadably engaged with the housing 1459 of theflashlight 1450 such that, by manually turning the actuator 1458, thelens 1457 and reflector 1456 move axially with respect to the incoherentlight, thereby changing the focus/shape of the incoherent light beam.

It should be understood that the LCM embodiments described above are forillustrative purposes only and should not limit the claims. Other LCMembodiments will be obvious to those of skill in the art in light ofthis disclosure.

CLED

As used herein, the CLED may be one or more solid state devices thatemits coherent light along an optical path having an optical axis. Inone embodiment, the CLED is at least one of a laser, an array of lasers,a superluminescent diode (SLD), or an array of SLDs. Examples of lasersinclude, for example, a vertical cavity surface emitting laser (VCSEL),and side emitting lasers, such as a double channel, planar buriedheterostructure (DC-PBH), buried crescent (BC), distributed feedback(DFB), or distributed bragg reflector (DBR). In one particularembodiment, the CLED is a VCSEL, which can provide a very small circularspot. Another benefit of a VCSEL is that it emits light in the sameorientation as LEDs, making them amenable to surface mount packaging.Edge emitting laser diodes also provide a narrow spot, but their beam iselliptical and is more challenging to integrate in a surface mountconfiguration. In one particular embodiment, the CLED is a SLD, whichcombines the directionality typical of laser diodes with the spectralwidth of LEDs. A SLD reaches amplified spontaneous emission conditionsbut does not lase (stimulated emission) resulting in a low temporalcoherence thus leading to speckle-free illumination seen inedge-emitting lasers.

The CLED(s) may be packaged in different ways. For example, in oneembodiment, the CLED may be a single discrete device or it may beassembled or integrated as an array of devices. Additionally, the CLEDmay be discrete chips, an array on a chip, or discrete chips in anarray. Moreover, a single package may comprise not only the CLED, butalso other elements (e.g., lenses, microlens arrays, down-converters,driver circuits, and LCMs) as described herein. For example, in oneembodiment, the CLED(s) may be packaged in a TO can (see FIG. 14 ), orin ceramic package (see, for example, FIGS. 3A and 3B), or with ametasurface to bend their optical path (see FIGS. 11A and 11B). In oneembodiment, the CLEDs are packaged with a metasurface to alter the pathof the coherent beam as shown in FIG. 12 . Specifically, in thisembodiment, RGB CLEDs are integrated with metasurfaces such that thecoherent beams from the CLEDs are focused on a point 1203 a of adiffuser 1203, thereby combining different color CLEDS into a diffusinglens. This may reduce complexity of combining RGB laser beams that istypically done with mirrors.

In one embodiment, the array of CLEDs comprises CLEDs configured foremitting coherent light having the same wavelength. In embodiments inwhich multiple CLEDs have the same wavelength, the CLEDs may be formedon a monolithic chip. Additionally, in applications in which multipleCLEDs have the same wavelength, one of more of the CLEDs may function asa pump for a down-converter (described below). Although different pumpwavelengths can be used to pump, in one embodiment, the pump light isblue (400-460 nm). Examples of commercially available blue pumps includeGaN blue edge emitting laser diodes from Nichia or OSRAM. GaN-based blueVCSELs are also in being developed. GaN blue superluminescent diodes arecommercially available by Exalos. Alternatively, in one embodiment, theCLEDs comprise violet (V) and/or ultraviolet (UV) CLEDs which arecoupled with a down-converter optical element to convert at least aportion of V and/or UV light to longer wavelengths. In one embodiment, Vand/or UV CLEDs are used without a down-converter, for example, forantibacterial applications polymer curing applications.

In one embodiment, the CLEDs are configured in an array in which two ormore of the CLEDs are configured for emitting coherent light ofdifferent wavelengths. In embodiments were multiple wavelengths areused, the CLEDs of different wavelengths may be formed on differentdies. Different dies of multiple wavelengths may then be combined on asubmount. Although this may be more expensive than preparing amonolithic chip with an array of CLEDs as mentioned above with respectto singular wavelength embodiments, if the application calls formultiple CLEDS for total optical output, this approach may make moresense.

In one embodiment, the array of CLEDs comprises separately controllabledrivers controlled by a control signal such that the output of at leasta portion of the array of CLEDs is variable based on the control signal.In one embodiment, the CLED is configured to emit any color, includingvisible light, such as red (R), green (G), blue (B), and violet (V). Forexample, referring to FIG. 2 , RGB CLEDs 201 a, 201 b, and 201 c areshown. Likewise, FIGS. 11B and 12 show alternative embodiments of usingRGB CLEDs. In one embodiment, non-visible wavelength such as ultraviolet(UV) and/or infrared (IR) CLEDs may be used. In one embodiment, theCLEDs comprises only RGB CLEDs. In one embodiment, the CLEDs comprisesRGB CLEDs plus one or more UV, V, and/or IR CLEDs, for example, for fullspectrum color and/or circadian rhythm and/or antibacterial applications(as discussed below).

In one embodiment, the illumination source uses a combination of pumpCLEDs and non-pump CLED. For example, in one embodiment, blue CLEDs(400-460 nm) are used for pumping, and additional CLEDS, for example,480 nm, are used to achieve the desired spectrum/quality of light.

As is well known, CLEDs are driven by driver circuitry. This circuitrymay be configured in different ways. For example, in one embodiment, onedriver may drive multiple CLEDs, and, in another embodiment, each CLEDmay have a discrete driver circuit. In one embodiment, the drivercircuitry is integrated with printed circuit board (PCB) upon which theCLED substrate or package is mounted. Alternatively, the drivercircuitry may be integrated in a TO can as is well known. Still otherdriver circuitry configurations/packaging will be known to those ofskill in the art in light of this disclosure.

Optical Element

The optical element functions to convert coherent light to incoherentlight. To this end, the optical element will have differentconfigurations depending on the illumination source configuration andthe CLEDs used. For example, in an embodiment, in which the CLEDs havethe same wavelength, the optical element may be configured as at leastone down-converter for converting at least a portion of the coherentlight to converted light having one or more different wavelengths suchthat the incoherent light is a combination of light having thewavelength and the different wavelengths. The down-converter may be anyknow material or device for receiving light of one wavelength andemitting light of a different, typically longer, wavelength. Suchmaterials and devices are well-known and include, for example, phosphor,quantum dots, perovskites and/or other materials designed to downconvert some, most or all of the energy to a different wavelength. Forexample, referring to FIGS. 1A & 1B, 5 a & 5B, 9, 10, and 11A, theoptical elements 103, 503, 903, 1003, and 1103 a, respectively, aredown-converters configured to convert a portion of the coherent lightbeam to light having one or more longer wavelengths. Similarly,referring to FIG. 14 , the optical element 1403 comprises a phosphorwindow incorporated into a TO can 1401 for down converting light. Inthis embodiment, the typical glass window is replaced with phosphor inglass or ceramic phosphor as the window material. (Typically TO cans useglass lenses (various formulations) or sapphire lens.)

In one embodiment, the down-converter receives the coherent light of onewavelength and converts it to an incoherent white light, which may havedifferent qualities as described below. In some embodiments, thedown-converter may convert all of the CLED coherent light or just aportion of the CLED coherent light, allowing the remaining portion toleak in the emission of the illumination source. Applications willdictate whether to leak certain wavelengths to attain, for example,full-spectrum color, defined ultraviolet and/or violet peaks forantibacterial purposes, or increase or decrease blue peaks for circadianregulation as discussed below in greater detail. Again, one of skill inthe art will understand how to configure the spectrum to achieve thedesired result in light of this disclosure.

The down converting may be configured in different ways. For example, inone embodiment, the down converting optical element is configured as asingle element such as the optical element 403 in FIG. 4A.Alternatively, in another embodiment, it may be configured as an arrayof elements 703 as shown in FIG. 7 . In this particular embodiment, aglass plate with phosphor sections 750 may be aligned along the opticalpath of the coherent light from the CLEDs. For example, referring toFIG. 8 , an aligned view of the CLEDs, MEMS 606, and phosphor array 705is shown with drivers on a PCB.

In one embodiment, the optical element is a diffuser for combining thecoherent light having different wavelengths such that the incoherentlight is a combination of light having the different wavelengths. Inother words, in an embodiment in which CLEDs of different wavelength areused, the optical element need not necessarily be a down-converter, andmay be instead a diffuser to combine the different wavelengths ofcoherent light into an incoherent emission light. Diffusers arewell-known and will not be discussed herein in detail. Suffice to saythat a diffuser is typically configured to mix the various coherentlight sources evenly to generate a homogeneous incoherent emission. Forexample, referring to FIGS. 2, 11B and 12 , the optical elements 203,1103 b, 1203, respectively, are diffusers for combining the differentcoherent emissions from RBG CLEDs.

It should be understood that when configuring the down-converter,thermal management of down-conversion media under high optical fluxdensity should be addressed. For example, in one embodiment, thedown-converters are heat sunk. In one embodiment, thermally conductivemedia (e.g. thermally conductive glass) surrounds the phosphor to removethe heat from the down-conversion process. Alternatively, in oneembodiment, a single crystal ceramic phosphor is used to improve thethermal performance. Alternatively, the laser beams from an array ofCLEDs can help spread the optical density load on the phosphor.

Although the embodiments illustrated herein show the down-converterdownstream of the LCM lenses along the optical path of the coherentlight, alternatively, they may be upstream of the LCM lenses. In oneembodiment, an illumination source having a piezoelectric actuator isconfigured with the down-converter disposed upstream of the LCM lens(es)along the optical path of the coherent light.

The various embodiments of the LCM, CLED(s), and optical elementdisclosed herein can be mixed and matched in differentcombinations/permutations to form illumination sources other than thosedescribed herein. Such permutations of the LCM, CLED and optical elementwill be obvious to those of skill the art in light of this disclosure.

Spectrum

The emitted incoherent light may be configured to suit the application.For example, in some applications full-spectrum white light may bedesired, in others, moderation of circadian cycles may be the objective,and it still other applications antimicrobial light may be the goal.More specifically, systems according to the principles of the presentdisclosure may be arranged to produce a spectrum tailored to providedisinfection (e.g. a spectrum that includes violet and/or UV), healthylighting (e.g. a spectrum that effects circadian rhythms of thoseexposed to the spectrum), full spectrum lighting (e.g. a spectrum thathas energy in most or all of the visible spectrum), a narrow band oflight (e.g. a spectrum with energy in the UV, visible and/or theinfrared), and/or several narrow bands of light, etc.

In one embodiment, the combination of light from the array of CLEDs iswhite light. In embodiments designed to be full spectrum, which may ormay not include disinfection light and/or circadian effective light, thespectrum is configured for acceptable color temperature with high CRIand high lumens per watt. For example, the CLEDs, with and/or withoutphosphors, may be arranged to produce energy throughout all or most ofthe visible spectrum to produce a color temperature between 2700 and6000K, or higher (e.g. 10,000k) with a CRI of greater than 80, 90, ormore. In one embodiment, the white light has a correlated colortemperature of between 2700k and 10000k and a color rendering index ofover 80.

Applications for full-spectrum white light include not only residentialand commercial lighting applications, but also medical deviceapplications in which the light source is coupled to an optical fibersuch as laparoscopy, endoscopy, laryngology, etc. In this respect,currently xenon light sources or LED based light sources are used forfiber lighting in minimally invasive surgical procedures. However, theoptical coupling of a coherent light-based illumination source is betterthan LED/xenon light sources.

In one embodiment, the combination of light from the array of CLEDsincludes a violet component sufficient to have an antibacterial effect.In another embodiment, the combination of light includes a UV componentsufficient to have an antibacterial effect. In one embodiment, thecombination of light has a spectral power distribution (SPD), whereinthe power of the violet portion of the SPD is at least 25%, at least30%, at least 35% or at least 40% of the overall power of the SPD. Inone embodiment, the violet component comprises a peak wavelength of atleast one of 395 nm or 405 nm. In embodiments including violet light,the violet light may be within the energy range of 380 to 420 nm. Theviolet light may be continuous (e.g. using a violet or ultra-violet CLEDwith a down conversion material) within the range or discontinuous (e.g.using a violet CLED without using a down conversion material), it mayfill the range, or it may not fill the range. For example, the violetmay include a CLED that produces light around 405 nm and pump a phosphorsuch that there is a narrow band at 405 nm and a continuous spectrum atlonger wavelengths. A 405 nm CLED may not pump a phosphor such that theenergy does not get down converted and remains coherent or is madenon-coherent by projecting the energy through another structure. A 405nm CLED may not pump a phosphor but it may be converted into anincoherent beam. 405 nm is just one example. The violet may be generatedby other CLEDs, such as 395 nm or shorter or longer, 410 nm or shorteror longer, etc. The violet may also result from a combination of CLEDswithin the violet range (e.g. a combination of 395 with and/or withoutphosphor and 405 nm with and/or without phosphor). Each CLED may becontrollable such that color mixing ratios and light intensities can beadjusted in a dynamic or static fashion.

In one embodiment, the combination of light includes energy within amelanopic curve adapted to affect circadian rhythms of a person exposedto the combination of light. In one embodiment, the energy within themelanopic curve is controllable between high and low energy based on thecontrol signal. In embodiments designed to affect a person's circadianrhythms, the light may be tailored to produce energy maximized to amelanopic curve. The curve spectrum is generally described by a normallydistributed curve between 400 and 600 nm (e.g. with most effectivenessbetween 450 and 525 nm), as compared to the normally distributedphotopic curve between 380 and 800 nm. It should be understood that themelanopic curve may or may not be normally distributed and the generalenergy range may change as more is learned about a person's response tocircadian effective lighting. A system designed to effect a person'scircadian rhythms may also provide dynamic or controllable light levelswithin the effective range. For example, at night, when a person istrying to wind down and go to sleep the energy delivered in themelanopic range could be reduced so as to encourage the body to releasemelatonin. If the person is trying to wake, energize or stay alert, theenergy delivered in the melanopic range could be high to suppressmelatonin production. Such a system may have a CLED arranged to pump aphosphor to generate, for example, a broadband cyan color and this CLEDsenergy may be controlled to deliver the correct amount of melanopicenergy for the situation.

LiFi

In one embodiment, the illumination source of the present invention isintegrated with LiFi. LiFi is high speed bidirectional network for thewireless communication of data using light. LiFi is generally considereda two-way data communication, whereas visual light communication (VLC)tends to be a one-way communication. In this embodiment, theillumination source is configured to communicate data wirelessly (i.e.in a downlink channel) by emitting modulated light from a luminaire.Specifically, the coherent light is modulated such the light emittedfrom the luminaire communicates data. This modulation of coherent lightis however imperceptible to the human eye. In one embodiment, thereceiver of the emitted modulated light (e.g. a laptop computer, smartphone, etc.) is configured to communicate data wirelessly to theluminaire (i.e. the uplink channel). In one embodiment, the uplinkcommunication uses nonvisible light (e.g. IR light).

FIGS. 13A-13E show various embodiments of LiFi being integrated into aluminaires having illumination sources of the present invention. Forexample, referring to FIG. 13A, luminaire 1300 a comprises a pluralityof CLEDs 1301 a mounted to a heatsink/sub mount for emitting coherentlight along the pathway, an array of lenses 1305 in the pathway, and anLCM 1304 comprising a microlens array 1305 in the optical pathway of thecoherent light and an actuator 1306 for moving the microlens array 1305.The optical element in this embodiment is a down-converter 1303 a. Inthis particular embodiment, the luminaire 1300 a also comprises a LiFiaccess point to ethernet/POE switch, and, optionally, a receiver foruplink 1351.

In one embodiment, the illumination source is used for the downlinkconnection by modulating the coherent light. In one embodiment, theincoherent light it is modulated. In one embodiment, a luminaire isconfigured with a nonvisible light receiver for receiving the uplinkdata.

In one embodiment, CLEDs of different wavelengths are discretelymodulated to facilitate the use of wavelength division multiplexing(WDM) to enhance LiFi speeds compared to, for example, a single channelLiFi with a blue CLED. For example, in one embodiment, the multiplewavelength CLEDs comprise an RBG array. The individual wavelength CLEDsmay be discretely modulated to communicate different signals, but, whencombined, form white light. Additional CLED colors can be added to notonly improve the color rendering index (CRI) but add additional channelsfor WDM purposes—e.g. amber and/or cyan CLEDs may be added. In oneembodiment, pump CLEDs (e.g. blue CLEDS) having slightly differentwavelengths (e.g. 430 nm, 440 nm, 450 nm) may be separately modulated tocommunicate different signals, yet each functions to pump a commondown-converter.

The other embodiments shown in FIGS. 13 B-F are similar to 413 aalthough may comprise different configurations of CLEDs, different LRMsand different optical elements as described herein.

Having thus described a few particular embodiments of the invention,various alterations, modifications, and improvements will readily occurto those skilled in the art. Such alterations, modifications, andimprovements as are made obvious by this disclosure are intended to bepart of this description though not expressly stated herein, and areintended to be within the spirit and scope of the invention.Accordingly, the foregoing description is by way of example only, andnot limiting. The invention is limited only as defined in the followingclaims and equivalents thereto.

What is claimed is:
 1. An illumination source, comprising: at least onecoherent light emitting device (CLED) configured for emitting coherentlight having an optical path; at least one optical element in saidoptical path for converting at least a portion of said coherent light toincoherent light, said optical element being configured to emit saidincoherent light in a direction; and a light control mechanism (LCM) foraltering said direction of said incoherent light. 2-31. (canceled)